Semantic web as a vision of Tim Berners-Lee is highly dependable upon the availability of machine readable information. Ontologies are one of the different machine readable formats that have been widely investigated. Several studies focus on how to extract concepts and semantic relations in order to build ontologies. Wikipedia is considered as one of the important knowledge sources that have been used to extract semantic relations due to its characteristics as a semi-structured knowledge source that would facilitate such a challenge. In this paper we will focus on the current state of this challenging field by discussing some of the recent studies about Wikipedia and semantic extraction and highlighting their main contributions and results.